1. Field of the Invention
The present invention relates to a mobile terminal apparatus, character input method and character input program for character input using a key operation.
Priority is claimed on Japanese Patent Application No. 2005-17305, filed Jan. 25, 2005, the content of which is incorporated herein by reference.
2. Description of Related Art
In a mobile terminal apparatus which provides a mailing function, in order to accept character inputs such as sentences in a mail, predetermined alphabetic characters are assigned to dialing keys (ten keys from “0” to “9”), and character inputs are made by selecting the desired dialing keys. For example, when inputting Japanese, characters included in the “a” column, “ka” column, . . . , “ra” column and “wa, wo, n” are assigned to each of the above ten key buttons, and it is determined that “i” is input when the key assigned to the “a” column is pushed twice and “u” is input when the key assigned to the “a” column is pushed three times. It becomes possible to send mails easily from outside by operating the dialing keys of the mobile terminal apparatus having such a function.
Moreover, dull sounds and “pa”, “pi”, “pu”, “pe” and “po” are often used, and a character input apparatus which simplifies the method to input such characters is known (for example, see Japanese Unexamined Patent Application, First Publication No. 2004-030442).
However, a language which uses characters that have tone signs, for example Vietnamese, has many alphabetic characters. For example, in Vietnamese, as shown in FIG. 5, as well as the 26 characters of the English alphabets, there are 6 vowel characters and one consonant character which are unique to Vietnamese (therefore, Vietnamese has unique 7 alphabetic characters), and each of 12 kinds of vowel characters have combination characters to which 5 different kinds of tone signs are appended, therefore, the total number of characters which are used is 93. The number of characters which are assigned to one key becomes large when these characters are assigned to ten dialing keys (ten key), therefore, there is a problem in that the numbers of a key needs to be pushed in order to select one character from the characters assigned to a key increases according to the number of characters assigned to the key. Moreover, it is difficult to print characters assigned to the key on the key face when a large number of characters are assigned to one key; therefore, there is also a problem in that the operation of inputting characters becomes complex since a user needs to refer to a manual or the like to detect which key to push to select a desired character.
The present invention has been made in order to solve the problems above, and an object thereof is to provide a mobile terminal apparatus, character input method and character input program which allows easy input of characters by a key operation.